Most plants do poorly when flooded. Certain rice varieties, known as deepwater rice, survive periodic flooding and consequent oxygen deficiency by activating internode growth of stems to keep above the water. Here, we identify the gibberellin biosynthesis gene, SD1 (SEMIDWARF1), whose loss-of-function allele catapulted the rice Green Revolution, as being responsible for submergence-induced internode elongation. When submerged, plants carrying the deepwater rice–specific SD1 haplotype amplify a signaling relay in which the SD1 gene is transcriptionally activated by an ethylene-responsive transcription factor, OsEIL1a. The SD1 protein directs increased synthesis of gibberellins, largely GA4, which promote internode elongation. Evolutionary analysis shows that the deepwater rice–specific haplotype was derived from standing variation in wild rice and selected for deepwater rice cultivation in Bangladesh.
大多數(shù)植物在淹水時(shí)表現(xiàn)不佳。被稱為深水稻的某些水稻品種，通過激活莖的節(jié)間生長保持在水面上，從而在周期性淹水和隨之而來的缺氧中生存。在此，我們確定了赤霉素生物合成基因SD1，其功能缺失等位基因引發(fā)了水稻的綠色革命，是淹水誘導(dǎo)節(jié)間伸長的原因。當(dāng)沉入水中時(shí)，攜帶深水稻特有的SD1單倍型的植物會放大一個信號傳遞，其中SD1基因被乙烯應(yīng)答轉(zhuǎn)錄因子OsEIL1a激活。SD1蛋白可促進(jìn)赤霉素（主要是GA4）的合成，促進(jìn)節(jié)間伸長。進(jìn)化分析表明，深水稻特有的單倍型來源于野生稻的直立變異，并被選為孟加拉國的深水稻栽培。